1. Field of the Invention
The present invention relates to a drum-type washing machine, and more particularly, to a drum-type washing machine employing a lift provided with a friction plate for increasing a frictional force acting on laundry.
2. Discussion of the Related Art
Generally speaking, laundering using a drum-type washing machine is carried out using a frictional force between the laundry and a rotating drum that receives the driving force of a motor. Such a method causes little damage to the laundry, prevents the laundry from getting tangled, and achieves such washing effects as beating and rubbing.
FIG. 1 illustrates a drum-type washing machine according to a related art, having a plurality of lifts 1 axially installed on the inner circumferential surface of a drum. An example of such a lift is shown in FIG. 2.
Referring to FIG. 1, a cylindrical drum 2 for receiving and washing laundry is mounted within a tub 8 for holding washing water, such that the drum lies parallel with respect to a foundation. A rotational shaft 7 is connected to the drum 2 to rotate the drum forwardly and reversely, thereby the laundry to be washed inside the drum. This rotating action results from a rotating force transferred to the drum 2 using an electrical motion system made up of a motor 3 that drives a belt 5 linking a pair of pulleys 4 and 6, thus allowing full directional control of the rotation of the drum.
Each lift 1 has a regular trapezoidal cross-section and inclined sides 1a and 1b having smooth faces. Typically, the lifts 1 are made of a metal or plastic material.
In the operation of a drum-type washing machine constructed as above, laundry is placed in the drum 2, water is supplied to the tub 8, and the rotational shaft 7, driven by the motor 3, rotates the drum. As the drum 2 rotates, the laundry is lifted by at least one of the lifts 1, from a lower area of the drum's interior and up one side of the interior, until reaching a point where the inclined side 1a or 1b passes a plane level to the foundation, whereupon the lifted laundry falls back down to the drum's lower area. The laundry is thus washed by a combination of actions occurring in the washing water, including the drum's rotation and the laundry's lifting and falling. As the drum 2 rotates, the laundry is lifted and falls to produce a sudsing action in the washing water.
In the drum-type washing machine according to the related art, the smooth faces of the inclined sides 1a and 1b provide limited frictional force on the laundry. As a result, the lifting action is also limited, so that the laundry slides from the lift too soon, to fall only a short distance, which creates only a light sudsing action. Optimum washing, however, requires vigorous sudsing.
As above, the frictional force acting on the laundry in the drum-type washing machine of the related art is insufficient. Moreover, with larger and heavier laundry loads, the necessary frictional force is even greater. Therefore, the washing performance of the drum-type washing machine of the related art is less than optimum.